For Andre Villas-Boas, it felt like a defining moment. His players hugged, the away fans in the far corner roared and his face, which has worn a frown for so much of his time in English football, was wreathed in a smile.

It was a rare sight and a welcome one, too. The Portuguese is not a figure who naturally attracts sympathy, such is his air of purpose and certainty.

His name was mud in English football for the manner in which he failed at Chelsea, and it took quite a leap of faith from Tottenham in the summer to give him a second stab at a leading Premier League club.

Those senior Spurs officials involved in the controversial decision to sack Harry Redknapp and replace him with ‘AVB’ can feel ever-so-slightly smug with themselves this evening.

To Redknapp’s legion of media followers, it felt like shooting Bambi. To those who prowl the White Hart Lane corridors of power, it was a very necessary culling.

The method in what many claimed was madness was clear to see at Old Trafford as Spurs annexed a horror run at what had become, for them, the Theatre of Nightmares.

The statistics were compelling ones – 26 matches between the two sides at United’s home ground in 22 years, 23 of which had ended in a victory for Sir Alex Ferguson’s team.

Whatever the masses think of Villas-Boas, he doesn’t do fear and it was apparent in the confident manner his team set about their evening’s work.

Perhaps an extra degree of motivation had been provided by a report that might have found its way to the Portuguese’s breakfast table, which claimed that Spurs were in turmoil and there was an air of mutiny around the squad due to the new manager's training methods.

Well, if a transformation leads to three consecutive league wins all achieved in a style of which Tottenham supporters feel is synonymous with their club, culminating in an historic win at the home of the Premier League favourites, then to hell with moans about a few double training sessions.

United supporters would be right to feel hard done by, given the spirit and conviction of their second-half comeback, in which they scored two goals in 140 seconds soon after the break, twice hit the woodwork and completely dominated the play.

But that fails to take account of the majesty of Spurs’ first-half display. So crisp was their passing and so electric were their counter-attacks that many in the away end who have witnessed such misery down the years at this ground would have been pinching themselves.

Villas-Boas admitted he had got it wrong in the first half against QPR last weekend, when he dropped Gareth Bale to left-back and allowed Rangers to control the opening 45 minutes at White Hart Lane.

Not this time. He set Spurs up in the 4-2-3-1 formation that has become the hallmark of White Hart Lane reign and urged them to throw numbers forward when they had the ball. Crucially, he targeted the right flank, where Nani is not known for desire to track back and Rafael Da Silva’s defensive skills are highly questionable.

Jan Vertonghen started where he finished off in the second half last Sunday, at left-back, and gambolled forward like a latter-day Roberto Carlos as he broke to score the first, nearly scored a second and caused panic every time he lurched beyond the half-way line.

Villas-Boas also got the three other big selections right. Steven Caulker kept his nerve alongside William Gallas during United’s second-half onslaught and demonstrated the rich promise that has seen him leapfrog above Redknapp favourite Michael Dawson.

Clint Dempsey, preferred to Gylfi Sigurdsson, did what he does best, breaking from a support striker role to apply the finish for Spurs’ third, while Brad Friedel was a composed presence in goal when bums began to squeak late on. Poor Hugo Lloris might have to wait some time to make his Premier League bow.

But, it was Mousa Dembele who really caught the eye, even ahead of the incisive Bale, who brilliantly finished Spurs’ second after leaving Rio Ferdinand trailing in his wake and had the parried first-time shot that broke for the third.

For the second time at Old Trafford this season - the first being in a Fulham shirt - the Belgian was a massive figure, driving forward purposefully with the ball, winning tackles and closing down the space in which Paul Scholes and Michael Carrick love to operate.

One joke doing the rounds is that Dembele has already won more man-of-the-match awards at the Theatre of Dreams this season than anyone in the United midfield will. That would be unfair on Scholes, who was as influential in the second half as Dembele in the first, but you could see the point.

United tried to sign the Belgian in the final week of the transfer window, but many of their fans will feel they didn’t try hard enough.

He is already a crucial cog in Villas-Boas' increasingly well-oiled machine. They rode their luck in the second half but it never left as if they lost their heads or their shape.

This victory was a triumph for the Portuguese’s tactical acumen and confidence in upsetting some considerable odds. Undoubtedly, it was his finest moment in English football.